Are they really that bad? That would make them no improvement MPG-wise on the 1.6 they replaced.
No they aren't and whoever has one that isn't getting good mpg is driving it incorrectly. Yes the mpg won't achieve the stated figures, but that is true for the majority of manufacturers. Audi recently were taken to task by the advertising standards for making unreasonable claims over the mpg of one of its vehicles.
As we have a 100ps 1.0 ecoboost fiesta I think that getting 58mpg at a steady 80-85mph is very good.
Then of course you have the fact that they're much more fun to drive than the 1.6 versions were...